A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6110-01-064-3801
NSN 5985-00-176-1499
NSN 5905-00-825-3614
NSN 5895-00-238-4618
NSN 5985-01-473-1176
NSN 5910-00-165-0629
NSN 5996-00-951-8136
NSN 5910-01-007-2577
NSN 5855-01-495-2670
NSN 6610-01-209-2524
NSN 6150-00-775-5840
NSN 5910-01-204-7223